Reply to this post, and I will pick five of your icons that I want to hear about.

Make a post (including the meme info) and talk about the icons I chose.

Other people can then comment to you and make their own posts.

This will create a never-ending cycle of icon glee...

This is Angela from the webcomic Punch an' Pie. For obvious reasons, I use it when a maniacal grin seems appropriate.

This is a green dwagon (sic) from the webcomic Erfworld. (Many of the creature names are deliberately cutsified, which makes for an interesting contrast with the seriousness of the story.) I don't really have a definite pattern for when I use this one.

This is an animation I created from an image of Jillian from Erfworld writing a report. I occasionally use it to suggest "just jotting something down," though not too often since I don't want to overuse animated icons.

Jillian again, charging on gwiffonback (sic -- see above). I tend to use this one a bit whimsically -- the original scene is dramatic, but it's somebody riding a giant flying marshmellow peep, after all.

This is Prince Ansom and one of his allies from Erfworld, pondering a map while formulating a plan. I tend to use this one for gaming-related posts.